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CVE-2026-31444 (GCVE-0-2026-31444)

Vulnerability from cvelistv5 – Published: 2026-04-22 13:53 – Updated: 2026-08-05 12:22
VLAI
Title
ksmbd: fix use-after-free and NULL deref in smb_grant_oplock()
Summary
In the Linux kernel, the following vulnerability has been resolved: ksmbd: fix use-after-free and NULL deref in smb_grant_oplock() smb_grant_oplock() has two issues in the oplock publication sequence: 1) opinfo is linked into ci->m_op_list (via opinfo_add) before add_lease_global_list() is called. If add_lease_global_list() fails (kmalloc returns NULL), the error path frees the opinfo via __free_opinfo() while it is still linked in ci->m_op_list. Concurrent m_op_list readers (opinfo_get_list, or direct iteration in smb_break_all_levII_oplock) dereference the freed node. 2) opinfo->o_fp is assigned after add_lease_global_list() publishes the opinfo on the global lease list. A concurrent find_same_lease_key() can walk the lease list and dereference opinfo->o_fp->f_ci while o_fp is still NULL. Fix by restructuring the publication sequence to eliminate post-publish failure: - Set opinfo->o_fp before any list publication (fixes NULL deref). - Preallocate lease_table via alloc_lease_table() before opinfo_add() so add_lease_global_list() becomes infallible after publication. - Keep the original m_op_list publication order (opinfo_add before lease list) so concurrent opens via same_client_has_lease() and opinfo_get_list() still see the in-flight grant. - Use opinfo_put() instead of __free_opinfo() on err_out so that the RCU-deferred free path is used. This also requires splitting add_lease_global_list() to take a preallocated lease_table and changing its return type from int to void, since it can no longer fail.
Severity
9.8 (Critical)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 302fef75512b2c8329a3f5efab1ae7ba2562387a , < 9e785f004cbc56390479b77375726ea9b0d1a8a6 (git)
Affected: 08aa9f3c8cf4d0bee44df540dfe34e8d64069f2c , < 7de55bba69cbf0f9280daaea385daf08bc076121 (git)
Affected: 1d6abf145615dbfe267ce3b0a271f95e3780e18e , < a5c6f6d6ceefed2d5210ee420fb75f8362461f46 (git)
Affected: ce8507ee82c888126d8e7565e27c016308d24cde , < 6d7e5a918c1d0aad06db0e17677b66fc9a471021 (git)
Affected: 1dfd062caa165ec9d7ee0823087930f3ab8a6294 , < 48623ec358c1c600fa1e38368746f933e0f1a617 (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.6.130 , < 6.6.131 (semver)
Affected: 6.12.78 , < 6.12.80 (semver)
Affected: 6.18.19 , < 6.18.21 (semver)
Affected: 6.19.9 , < 6.19.11 (semver)
guessed Create a notification for this product.
Show details on NVD website
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    "redhat_vex": {
      "aggregate_severity": "None",
      "current_release_date": "2026-06-28T06:27:35+00:00",
      "cve": "CVE-2026-31444",
      "id": "CVE-2026-31444",
      "initial_release_date": "2026-04-22T00:00:00+00:00",
      "product_status:known_not_affected": "274",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ksmbd: fix use-after-free and NULL deref in smb_grant_oplock()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-31444.json",
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      "current_release_date": "2026-09-11T01:32:04Z",
      "cve": "CVE-2026-31444",
      "id": "CVE-2026-31444",
      "initial_release_date": "2026-04-23T01:26:21Z",
      "product_status:known_affected": "130",
      "product_status:known_not_affected": "284",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-31444",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-31444.json",
      "version": "5"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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